Brees flew to visit Dr. James Andrews for an "extensive evaluation" on Sept. 28, and the results were "very positive," ESPN's Ed Werder reported.

While Dr. Andrews (per Werder) confirmed Brees did not have a tear in his rotator cuff or throwing shoulder, NFL.com's Ian Rapoport noted on Sept. 27 that he'd been "told it’s actually a rotator cuff sprain (indicates some structural damage)."

Brees has been one of the NFL's most durable players over the past 12-plus seasons, having missed just two games during that time frame—both in Week 17, in preparation for the playoffs.

However, his future in New Orleans is in peril, with Jason Cole of Bleacher Report saying the Saints are "unlikely" to extend Brees past 2016 after the injury:

The 36-year-old entered the 2015 season having played in all 16 games for five straight years. He has also been one of the league's most productive passers during that time.

Brees entered the 2015 campaign with a bit of a chip on his shoulder after missing the playoffs and falling just short of the 5,000-yard passing threshold last season for the first time since 2010, according to ESPN.com's Mike Triplett.

"Maybe there's a slight bit of motivation," Brees told Triplett in July. "My mentality doesn't change from year to year. I always feel like there's something to prove. I approach every day, practice, rep, game as if I have something to prove. Never that I've arrived."

New Orleans is in transition to some degree since it traded tight end Jimmy Graham to the Seattle Seahawks and dealt wide receiver Kenny Stills to the Miami Dolphins during the offseason. But Brees, as always, is the one true constant on that side of the ball.

However, Brees is the one who makes New Orleans' explosive offense go. With Brees back in the fold after a one-game absence, the Saints offense will look to get back on track in Week 4.